Waves and polarisation

At the moment, we are only concerned with progressive waves. It is very important that we remember:

Progressive waves transfer energy without transferring matter.

There are two types of progressive wave: either transverse, or longitudinal.

Transverse - Vibrations are at right angles to the direction of energy travel. Describing a wave as transverse therefore implies that two directions of motion associated with the wave must be at right angles to each other- these directions of motion are the direction of energy travel and the direction of particle motion. e.g. light, e.m. waves.